Centrifugal fan



June 6, 1944.

r F. FERRE CENTRIFUGAL FAN Filed Aug. 16, 1939 fig 5a INVENTORQ,

FEEDINANDO 1 5mg Brim Z49 ATTORNEYS and compensate for.

Patented June 6, 1944 I oau'rarruoar. ran Ferdinando Fer-n6, Milan,Italy; vested in the Alien Property Gustodian Application August 1c,1939, Serial No. 290.346

In Italy August 2'1 193s 4 Claims. (01. est-134) This invention relatesto centrifugal fans, and has for one of its objects the elimination ofthe defects ordinarily incident to such fans. As now generallyconstructed, centrifugal fans are formed with cast rotors, with sheetmetal rotors, or with sheet metal parts combined with forged or castparts.

Fans with cast rotors are objectionable because they are diillcult tomaintainin balance at high speeds and also because their speed ofrotation is limited, in as much as stresses incident to the relativelygreat weight of the cast material develops rapidly as the speedincreases, whereby the resistant limits of the material is soonexceeded.

The sheet metal fans are objectionable because the various members areconnected by rivets or electric welds, which tend to unbalance the rotorin positions and to extents quite difllcult to detect When the sheetmetal parts are combined with forged or cast parts, the latter aregenerally limited to hub or spider parts to which the former areconnected by rivets or welds, offering the same objections above noted.In addition, welds often alter the brittleness or other properties ofthe material, particularly if not properly heat treated, and such heattreatment might itself cause warping. I

The use of centrifugal fans nowadays is extending to increasingly highertemperatures, both for circulation of heated air and for industrialpurposes, as ,for heat treatments in which the uniformity of temperaturehas a particular importance, and may be maintained only by a strongcirculation of the air or other heating medium. This is true not merelyfor relatively low temperatures (under 600 C.) in which-the convectionof the heat bears the greatest importance, but also forhighertemperatures in which heat radiation becomes more important, sincematerials are often made in compact bulk and only some of thesuperficial layers receive the direct action of the radiating heat.

The present invention will in large part ob- 1 viate the above defects.

stamped or machine parts with constant and uniformly distributedweights.

In the attached drawing are shown designs adapted for fans with a singlelateral inlet and for a' fan with two axial inlets, wherein 1 Fig. 1shows a central sectional view through my improved centrifugal fan witha single suction inlet.

Fig. 2 is a similar view of my improved fan ar-' ranged with two axialinlets.

Fig. 3 is a front elevation of the diskon which the fan blades shown inFig. 1 are mounted.

Fig. 3a is a section taken substantially on the central dotted line ofFig. 3.

' Fig. 3b is a front elevation of the disk on which the fan blades shownin Fig. 2 are mounted.

Fig. 4 is a front elevation of the hub.

Fig. 5 is a plan view, and Fig. 50- an edge view of a fan blade for asingle inlet fan, and

Fig. 6 isa plan view, and Fig. 6a an edge view of a fan blade for adouble axial inlet fan.

In thedrawing the reference character a designates a supporting diskmade of sheet metal and formed with a central aperture surrounded by aseries of upset extensions no as shown in blade useable in a singleinlet fan, and as best balancing of the fan, both because of thesymshown in Figs. 1 and 5 is formed with arcuate feet b and hooks j forpurposes presently to be described. As best shown in Fig. 3 the disk awhen used, for singleinlet fans is formed with spaced slots (1 ofrelatively short lengths and spaced radially and circumferentiallyaround the disk. The hOOks j of each fan blade e may be inserted throughthe slots d of the disk substantially as shown in Fig. 1, and whenproperly positioned the arcuate feet .b will complete a ring engagingthe inner faces of the upset portions a of the disk and the shaft c, ahub member h servingto secure'the assembled fan blades and disk on tothe shaft, substantiallyvas shown in Fig. 1. wherein a shoulder on theshaft retains the disk a from axial movement in one direction and thehub his pressed against the opposite face of the disk by threading thenut 1 upon the threaded end of the shaft. Obviously, other methods ofsecuring the disk blades and hub upon the shaft may be utilized.

In the construction of fans with a double axial air inlet, the disk a isformed with radial slots e' extending from the central aperture of thedisk into close proximity'to the periphery of the disk substantially asshown in Fig. 3b. Blades m extend through the elongated radial slots eand are formedsubstantially centrally of their outer edges with shortslots or notches 12, such slots or notches corresponding in length tothe distance between the outer edge of the radial slots e and theperiphery of the disk a. The duplex blades m are formed with arcuatefeet b, and may be secured upon the shaft in a manner similar to thatutilized with the single inlet fan. Thus after each blade m is insertedinto its respective slot until its notch palines with the disk, it isthen moved radially outward, the diameter of the central aperture in thedisk permitting initial positioning and then radial displacement intothe positions shown in Fig. 2. When moved into extreme radial positionthe feet b of the blades m will complete a ring engaging the upsetextensions Go of the disk a and the shaft, respectively. Half-hubs k maybe utilized for retaining the blades m in position, and a nut lcooperating with a shoulder upon the shaft may be used tohold the fanfrom axial movement thereon.

The above describes preferred adaptations of my invention and points outthe manner in which my invention may be utilized.

I claim: l

1. In a rotor for a centrifugal fan having hub means secured upon arotatable shaft and a plurality of spaced fan blades projecting radiallyfrom said hub means, the combination of a metal disk projecting fromsaid hub means in a plane of which is perpendicular to the axis of saidshaft and said disk having a diameter substantially equal to the extremeextension of said fan blades from the opposite sides of the hub means,the fan blades being made symmetrically of sheet metal and havingintegral intermediate radially disposed portions thereof engaging inslots extending outwardly from the central portion of said disk, so thatsaid blades are 'disposed symmetrically of-said disk in radial planessubstantially parallel to said axis of the shaft, and stamped or; bentintegral means disposed in the axial direction upon said disk in theportion thereof nearest the shaft and about the same and secured uponsaid hub means, and there being retaining means disposed upon the innerend of each fan blade at an angle to the general plane thereof forengaging with the hub means.

2. In a rotor for a centrifugal fan having hub means secured upon arotatable shaft and a'plurality of spaced fan blades projecting radiallyfrom said hub means, the combination of a metal disk projecting fromsaid hub means in a plane which is perpendicular to the axis of saidshaft and said disk having a diameter substantially equal to the extremeextension of said fan blades from' the opposite sides of the hub means,the fan blades being made of sheet metal and having integral portionsthereof engaging in slots in said disk extending radially therein fromthe central portion thereof, said integral portions on the bladesincluding hook portions lying substantially in the same planes with theblades from which they extend and in a direction substantially parallelto said axis of the shaft, and stamped or bent integral means disposedin the axial direction upon said disk in the portion thereof nearest theshaft and secured upon said hub means, and there being means upon theinner end of each fan blade for engaging with the hub means.

3. In a rotor for a centrifugal fan having hub means secured upon arotatable shaft and a plurality of spaced fan blades projecting radiallyfrom said hub means, the combination of sheet metal disk projecting fromsaid hub means in a plane which is perpendicular to the axis of saidshaft and said disk having a diameter substantially equal to the extremeextension of said fan blades from the opposite sides of the hub means,the fan blades being made symmetrically of sheet metal and havingintegral intermediate radially disposed portions thereof engaging in andextending through radially disposed slots in said disk in substantiallythe same planes with the blades from which they extend in a directionshbstantially parallel to said axis of the shaft, and integral retainingportions stamped or bent in the axial direction upon the disk adjacentto and secured upon said hub means, and there being retaining meansdisposed upon the inner end of each fan blade at an angle to the generalplane thereof for engaging with the hub means.

4. In a rotor for a centrifugal fan having hub means secured upon arotatable shaft and a plurality of spaced fan blades projecting radiallyfrom said hub means, the combination of a sheet metal disk projectingfrom said hub means in a plane which is perpendicular to the axis ofsaid shaft and said disk having a diameter substantially equal to theextreme extension of said fan blades from the opposite sides of the hubmeans, the fan blades being substantially plane, symmetrical sheet metalblades extending through elongated radially disposed slots in the diskfrom both sides of said disk, said elongated slots extending outwardlyfrom an open central area in the disk occupied by said hub means anddividing the major portion of the disk into a group of segments each ofwhich has a stamped or bent integral retaining means disposed in theaxial direction adjacent to and secured upon said hub means, and therebeing retaining means disposed upon the inner end of each fan blade atan angle to the general plane thereof for engaging with and beingretained by the hub means, said hub means having slotted portions forreceiving the retaining means of the disk segments and of the blades.

- -FERDINANDO FERRE.

